Novel dialkyl peroxydicarbonates

ABSTRACT

Novel solid, thermally safe and stable di-n-alkyl (tridecyl, tetradecyl, pentadecyl or hexadecyl) peroxydicarbonates; and the use thereof in polymerizing ethylenically unsaturated monomers and in curing unsaturated polyester resin compositions.

United States Patent [191 DAngelo NOVEL DIALKYL PEROXYDICARBONATES [75] Inventor: Antonio Joseph DAngelo, Buffalo,

[73] Assignee: Pennwalt Corporation, Philadelphia,

[22] Filed: July 30, 1970 [21] Appl. No.: 59,696

[58] Field of Search 260/463 [56] References Cited UNITED STATES PATENTS 2,370,588 2/l945 Strain 260/453 11] 3,821,273 June 28, 1974 3,720,700 3/1973 Norback 260/463 FOREIGN PATENTS OR APPLICATIONS 1,957,434 6/l970 Germany 978,875 12/1964 Great Britain ..260/463 Primary Examiner-Lewis Gotts Assistant Examiner-Diana G. Rivers Attorney, Agent, or Firm-William D. Mitchell, Esq.

[5 7] ABSTRACT Novel solid, thermally safe and stable di-n-alkyl (tride cyl, tetradecyl, pentadecyl or hexadecyl) peroxydicarbonates; and the use thereof in polymerizing ethylenically unsaturated monomers and in curing unsaturated polyester resin compositions.

4 Claims, No Drawings 1 NOVEL DIALKYL PEROXYDICARBONATES BACKGROUND OF THE INVENTION 1. Field of Invention 2. Related Art The novel di-n-alkyl peroxydicarbonates of this invention possess greater thermal stability and are less hazardous than art-related peroxydicarbonates such as di-n-dodecyl peroxydicarbonate and IPP (diisopropyl peroxydicarbonate, a major commercially available peroxydicarbonate).

Strain in U.S. Pat. No. 2,370,588 discloses the preparations of various dialkyl peroxydicarbonates, including di-n-dodecyl (dilauryl) peroxydicarbonate. Di-noctadecyl (stearyl) peroxydicarbonate is also listed. In U.S. Pat. No. 2,464,062, Strain also discloses that di-ndodecyl peroxydicarbonate is a useful initiator for vinyl polymerizations. In Strain et al., J.A.C.S., 72, l,254l,263 (1950), Strain further describes properties of several dialkyl peroxydicarbonates as shown in Table II at page 1,255. None of the Strain publications list the peroxydicarbonates of the subject invention.

U.S. Pat. No. 3,312,678 describes vinyl polymerizations employing dialkylperoxydicarbonate/tertiary aromatic amine systems as low temperature initiators. Din-dodecyl peroxydicarbonate is again listed as useful.

U.S. Pat. No. 3,373,]50 discloses processes for homo-and copolymerizations of vinyl chloride employing dialkyl peroxydicarbonate/diacyl peroxide combination initiator systems. Di-n-dodecyl and di-noctadecyl peroxydicarbonates are listed as being useful. The examples employ only dialkyl peroxydicarbonates having branched alkyl groups with carbons or less. The alkyl group is stated to preferably contain 8-10 carbons.

U.S. Pat. No. 3,324,097is similar to U.S. Pat. No. 3,373,150, except that no diacyl peroxides are employed. Instead, long chain aliphatic hydrocarbons, ethers and ketones are employed to reduce polymer build-up in polymerization vessels.

None of the above publications show the preparation and/or use of di-n-alkyl peroxydicarbonates in which the alkyl group contains more than 12 carbons. Di-noctadecyl (distearyl) peroxydicarbonate is often listed, but neither its preparation nor use are shown.

BRIEF SUMMARY OF THE INVENTION This invention concerns:

A. Thermally safe and stable di-n-alkyl peroxydicarbonates wherein the alkyl group has 13-16 carbons, namely di-ntridecyl, di-n-tetradecyl, di-n-pentadecyl and di-n-hexadecyl peroxydicarbonate. Di-n-hexadecyl peroxydicarbonate,

O I ll OHzlCHOuCHzOIi? O O C O CH:(CH2)1|CH3.

2 is preferred; and

B. Improved processes for l polymerizing ethylenically unsaturated monomers (such asvinyl chloride) which are responsive at suitable temperatures (and pressures) to initiating amounts of free radical generators as polymerization initiators and (2) curing unsaturated polyester resin compositions at curing tempera tures in the presence of initiating amounts of free radical polymerization initiators, the improvement residing in the use of the compounds of (A) as said initiator or curing agent.

DETAILEDDESCRIPTION OF THE INVENTION Dialkyl peroxydicarbonates are low temperature peroxides which are being increasingly used as low temperature free-radical polymerization initiators for ethylenically unsaturated monomers such as vinyl chloride. In the past diacyl peroxides such as di-ndodecanoyl (lauroyl) peroxide and di-n-decanoyl (decanoyl) peroxide have been used as free-radical initiators in vinyl chloride polymerizations. However, since these are higher temperature-peroxides, they have become less used and have been replaced by the lower temperature dialkyl peroxydicarbonates. The latter peroxides significantly cut down polymerization times, allowing a PVC (polyvinyl chloride) resin producer to make more polymer without having to invest in new plant equipment. The switch to the lower temperature dialkyl peroxydicarbonates was not made without problems, however. Dialkyl peroxydicarbonates, such as the major commercially available IPP (diisopropyl peroxydicarbonate), have stringent refrigerated storage and shipping requirements to maintain assay (active oxygen content) and must be handled for only a very short time at ambient temperatures (20-25C.)

due to their thermally explosive nature. On the other hand, the here-to-fore used diacyl peroxides such as din-dodecanoyl peroxide do not require expensive refrigeration for storage and shipping nor do they present ambient temperature explosive hazards. Thus there is a need in the polyvinyl chloride industry (as well as in other polymer industries) for a cheap, room temperature stable and safe (no ambient temperature rapid decomposition hazard) dialkyl peroxydicarbonate.

It has now been discovered that the following di-nalkyl peroxydicarbonates satisfy the above criteria:

Di-n-tridecyl peroxydicarbonate,

Di-n-tetradecyl peroxydicarbonate,

ll ll CHa(CHa)uCHzO 0-0 O-C O CHKCHQNCH;

Di-n-hexadecyl peroxydicarbonate.

All of these dialkyl peroxydicarbonates are solids, are stable at room temperature, have no ambient temperature rapid decomposition hazards and are potentially cheap sources of free-radicals. Di-n-tetradecyl and din-hexadecyl peroxydicarbonates can be prepared from low cost and commercially available n-tetradecanol and n-hexadecanol, respectively, and di-n-tridecyl and di-n-pentadecyl peroxydicarbonates can be prepared from C and C oxo alcohols or from n-tridecanol and n-pentadecanol, respectively. Thus the dialkyl peroxydicarbonates of this invention are all economically attractive to produce. On the other hand, the next higher members, di-n-heptadecyl and di-n-octadecyl peroxydicarbonates, are not commercially attractive since the former is made from very expensive nheptadecanol and the latter is obtained in low yields and assays and has a significantly lower activity on a weight basis than the dialkyl peroxydicarbonates of this invention. Furthermore, the latter, owing to manufacturing difficulties, will contain a significant amount of inactive organic material which will end up in the polymer when the latter is used as a free-radical initiator, hence lowering the quality and the utility of the resulting resin. in the case of the next lower member of this series of dialkyl peroxydicarbonates, di-n-dodecyl peroxydicarbonate is not thermally stable at room temperature and has significantly greater rapid decomposition hazards than the dialkyl peroxydicarbonates of this invention. Even though it is a solid (mp. 3032C.), di-n-dodecyl peroxydicarbonate loses all of its assay after one week at 30C., whereas the dialkyl peroxydicarbonates of this invention lose no assay (see Example Vlll). It also decomposes violently at 40C. after 90 minutes whereas the dialkyl peroxydicarbonates of this invention are stable to rapid decompositions at 40C., a temperature sometimes encountered in hot weather. The above results show that there is a sharp change in safety characteristics of dialkyl peroxydicarbonates (that is, from hazardous to nonhazardous) when going from di-n-dodecyl peroxydicarbonate to di-n-tridecyl peroxydicarbonate.

POLYMERIZATION In the free-radical initiated polymerization of ethylenically unsaturated monomers, the subject dialkyl peroxydicarbonates are found to provide molar efficiencies equal to or better than lPP and other artrelated dialkyl peroxydicarbonates.

Ethylenically unsaturated monomers include ethylene, propylene, styrene, alpha-methylstyrene, dichlorostyrene, p-chlorostyrene, vinyl naphthalene, vinyl phenol, vinyl toluene, vinylpyridine, divinylbenzene, acrylic acid and alpha-alkyl substituted acrylic acids such as methacrylic acid; the esters and amides of these unsaturated acids such as methyl acrylate, methyl methacrylate, butyl methacrylate, propyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, acrylamide and methacrylamide; the vinylidene halides such as vinylidene chloride, bromide and fluoride; vinyl esters of the inorganic acids, such as the halogen acids and hydrocyanic acid, as vinyl chloride, vinyl fluoride, vinyl bromide, acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl benzoate, vinyl valerate, vinyl caproate, vinyl propionate,

vinyl laurate, divinyl carbonate, divinyl succinate, divinyl adipate, vinyl allyl phthalate, vinyl methallyl pimelate, vinyl methyl glutarate, vinyl acrylate, vinyl crotonate and vinyl methacrylate; the vinyl ethers such as vinyl ethyl ether, vinyl butyl ether, vinyl allyl ether and vinyl methyl ether; the vinyl ketones such as vinyl butyl ketone and vinyl ethyl ketone; the allyl derivatives such as allyl acetate, allyl butyrate, diallyl phthalate, diallyl adipate, methallyl propionate, allyl chloride, methallyl chloride, allyl acrylate, methallyl methacrylate, allyl diglycol carbonate and diallyl carbonate; conjugated olefins such as butadiene, chloroprene and'isoprene; acrolein; maleic anhydride; maleic acid and fumaric acid and their esters; and perhalo olefins such as tetrafluoroethylene, hexafluoropropylene and chlorotrifiuoroethylene.

Temperatures of about 0-80C. are normally employed, with somewhat higher temperatures being emloyed in the case of high pressure ethylene polymerizations owing to pressure suppression of the rate of decomposition of the dialkyl peroxydicarbonates. The lower temperatures near 0C. are used where it is desired to use activated systems of the type described in U.S. Pat. No. 3,312,678. The preferred temperature range is 3575C.

Peroxide levels of about 0.003 to 0.300 percent or more by weight (preferably 0.0l0.20 percent), based on the polymerizable monomer, are normally employed in the polymerizations.

CURING OF POLYESTER RESINS.

In curing unsaturated polyester resin compositions by heating at suitable curing temperatures in the presence of free radical polymerization initiators, the use of the dialkyl peroxydicarbonates of this invention are found to give faster cures at low temperatures than dibenzoyl peroxide (an industry standard for polyester curing), in addition to their outstanding thermal stability characteristics.

Unsaturated polyesters which are used as the one component of the polyester resin compositions according to the present invention are, for instance, polyesters as they are obtained by esterifying preferably ethylenically unsaturated di-or polycarboxylic acid or their anhydrides, such as maleic acid, fumaric acid, glutaconic acid, itaconic acid, mesaconic acid, citraconic acid, allyl malonic acid, allyl succinic acid, and others, with saturated or unsaturated polyalcohols such as ethylene glycol; diethylene glycol (2,2-dihydroxy ethyl ether); triethylene glycol (ethylene glycol bis-(2-hydroxy ethyl ether); propanediol-l,2; butanedion-l,3; 2,2-dimethyl propanediol-l,3; butene (2)-diol-l,4, glycerol, pentaerythritol, mannitol, and others. Mixtures of such acids and/or alcohols may also be used. The unsaturated dior polycarboxylic acids may be replaced, at least partly, by saturated carboxylic acids such as adipic acid, succinic acid, sebacic acid, and others, or by aromatic dicarboxylic acids, such as phthalic acid, tetrahydrophthalic acid, and others and their anhydrides such as phthalic anhydride. The acids used as well as the alcohols employed may be substituted by other substituents, preferably by halogen. Examples of suitable halogenated acids are, for instance, tetrachloro phthalic acid; I, 4, 5, 6, 7, 7 -hexachloro bicyclo (2,2,1) heptene (5)-2,3-dicarboxylic acid, and others, or their anhydrides.

A preferred resin composition contains as the polyester component the esterification product of propylene glycol (a polyalcohol), maleic anhydride (anhydride of an unsaturated dicarboxylic acid) and phthalic anhydride (anhydride of an aromatic dicarboxylic acid) and as the monomer component styrene.

Temperatures of about 20l 50C. and peroxide levels of about 0.05 to 5.0 percent or more by weight of curable unsaturated polyester resin are normally employed.

In polymerization of the ethylenically unsaturated monomers, especially vinyl chloride polymerizations, it is further visualized that the long alkyl moieties of the subject dialkyl peroxydicarbonates will decrease their water solubility to such an extent that the formation of emulsion or water phase polyvinyl chloride will be diminished, thus decreasing the quantity of undesirable hard impenetrable polyvinyl chloride particles in the resin. Resin made from these peroxydicarbonates should therefore dissolve more easily and completely in standard solvents and plasticizers, and should extrude and form films free of such hard PVC particles;

EXAMPLES The following examples serve to illustrate the subject invention but are not in limitation thereof.

EXAMPLE I PREPARATION OF DI-N-HEXADECYL PEROXYDICARBONATE To a solution of 4.8g. (.12 mole) of NaOH and 100 ml. of water at 5C was added 4. lg. (0.06 mole) of 50 percent H A solution of 313g. (0.10 mole) of nhexadecyl chloroformate (97.5 percent assay) and 40 ml. of isopropanol was added slowly to the sodium peroxide solution at C 1' 2C over a period of 1 hour and the reaction was allowed to stir an additional 4 hours at 5 to C. The resulting mixture was poured into 800 ml. of cold water and the solid was separated by filtration. After washing several times with water the product was allowed to dry overnight at about C. This gave 28.2g. of granular solid having an active oxygen content of 2.25 percent and an active chlorine content of 0.67 percent. Hence, the assay of the product was 80.5 percent and the chloroformate content was 5 to 6 percent. The product was washed with methanol at 5C and the resulting dried product had an active oxygen content of 2.52 percent (90 percent assay), an active chlorine content of 0.28 percent about 2 percent chloroformate) and a melting point of 50 to 53C.The recovery in the methanol wash was 85 percent, hence the overall corrected yield was 77 percent. A sample of this product recrystallized from methylene chloride had a melting point of 50 to 54C and an assay of .97 percent acording to active oxygen content.

EXAMPLE II ALTERNATE PREPARATION OF DI-N-I-IEXADECYL PEROXYDICARBONATE A 0.5 mole preparation of the title peroxide at 35C, employing 700 ml. of hexane as a solvent for the nhexadecyl chloroformate gave the desired product in 89 percent corrected yield, and having an assay of 98 percent (based on active oxygen content) and a melting point of 52C.

EXAMPLE III PREPARATION OF DI-N-TRIDECYL PEROXYDICARBONATE FROM THE CHLOROFORMATE OF N-TRIDECYL ALCOHOL EXAMPLE IV PREPARATION OF DI-N-TRIDECYL PEROXYDICARBONATE FROM THE CHLOROFORMATE OF C OXO-ALCOHOL To a solution of 7.4g. (0. l 1 mole) of 50 percent H 0 and 30 ml. of H 0 at 5C was addeda solution of 44.0g. (0.22 mole) of aqeous 20 percent sodium hydroxide solution over a period of 15 minutes. To this vigorously stirred solution at 10C was added 52.4g. (0.20 mole) of the chloroformate prepared from a C oxo-alcohol (about 50 percent n-tridecyl alcohol and 50 percent 2- methyldodecyl alcohol) and phosgene. The resulting mixture was allowed to stir for 3 hours and the temperature rose to 27C. The product was then extracted with pentane and the pentane solution was cooled to 78C. A white solid came out of solution and, after separation by filtration, 20g. (41 percent of theory) of product was obtained having an assay of 100 percent (based on active oxygen" content) and a melting point of 45 C. A mixed melting point of this product with that of Example Ill (authentic di-n-tridecyl peroxydicarbonate) was taken. The results are shown below:

No. Peroxydicarbonate of m.p., C

1 This Example (IV) 45 2 Example Ill 43-45 3 50/50 (weight/weight) H2 4245 These results show that the product from this example is di-n-tridecyl peroxydicarbonate since no melting point depression was observed in the mixed melting point test.

EXAMPLE V PREPARATION OF DI-N-PENTADECYL PEROXYDICARBONATE FROM THE CHLOROFORMATE OF N-PENTADECYL ALCOHOL EXAMPLE VI PREPARATION OF DI-N-PENTADECYL PEROXYDICARBO- .NATE FROM THE CI-ILOROFORMATE OF r QXQ'A CO Following essentially the same procedure employed in Example IV di-n-pentadecyl peroxydicarbonate was tially cheap. The low yeild and assay obtained for di-noctadecyl peroxydicarbonate (No. 9, a peroxide mentioned in the prior art), and the lower theoretical activity of this dialkyl peroxydicarbonate shows that it is considerably more expensive to make and considerably less attractive to polyvinyl chloride resin manufacturers than the dialkyl peroxydicarbonates of this invention.

1. Solid portion of [he peroxydicar onate isolated 2. Solid portion of thc peroxydicarbonate isolated 97% assay material, m.p. 50 to 54C.

4. From Example I prepared from the chloroforrnate of a C oxo-alcohol (about 50 percent n-pentadecyl alcohol and'about 50 percent 2-methyltetradecyl alcohol). The product was obtained in 31 percent corrected yield and had an assay of 100 percent (based on factive oxygen content) and a melting point of 52 to 53C. A mixed melting point of this product with that of Example V (authentic di-npentadecyl peroxydicarbonate) was taken. The results are shown below:

No. v Peroxydicarbonate of mp, C

1 This Example (V1) 52 m 5,3 2 Example V 51 to 53 3 50/50 (weight/weight) 1/2 50 to 53 These results show that the product from this example is dl-n-pentadecyl peroxydicarbonate since no melting point depression was observed in the mixed melting point test.

EXAMPLE VII PREPARATIONS OF OTHER DI-N-ALKYL PEROXYDICARBONATES From Example 11 EXAMPLE VIII 30C. AND 40C. THERMAL STABILITY AND SAFETY TESTS 25 Gram samples of various dialkyl peroxydicarbonates were placed in thermostatted chambers held at 30C. and 40C. After various intervals of time (1 week, 2 weeks and 4 weeks at 30C. and up to 1 week at 40C). the percent loss of assay (active oxygen content) was noted. In addition, the thermal rapid decomposition character of the dialkyl peroxydicarbonate was noted. These data are summarized in Table II. The thermal stabilitydata show that the dialkyl peroxydicarbonates of this invention (Nos. 3, 4, 5, 6 and 6a in Table II) are stable at 30C. for one to four weeks, whereas the art-related dialkyl peroxydicarbonates (Nos. 1 and 2) lose practically all of their activity at 30C. in less than one week. In fact, lPP (No. 1) decomposed violently at 30C. after 10 to 15 minutes. Even in the case of a rather impure sample (No. of din-hexadecyl peroxydicarbonate (81 percent assay, m.p. 43 to 50C.) there was little loss of assay after 4 weeks at 30C. At 40C. after one week, di-n-hexadecyl peroxydicarbonate (No. 6) lost only 4 percent of its assay, a phenomenal observation in view of the fact that its half-life at 50C. in trichloroethylene is 9.9 hours and (from this) its estimated half-life at 40C. is about 40 hours. With respect to safety, the dialkyl peroxydicarbonates of this invention are stable to rapid decomposition at 30C. and 40C. whereas IPP (No. 1) decomposes violently after 10 to 15 minutes at 30C. and di-n-dodecyl peroxydicarbonate decomposes violently after minutes at 40C.

TABLE II 1 30C and 40C Thermal Stability and Safety Tests Thermal Stability Tests of Assay Lost at Assay m.p.. 30C 30C 30C 40C Safetv Tests at No. Peroxydicarbonate C 1 wk 2 wks 4 wks 1 wk 30C 40C I. Diisopropyl (IPP) 8 to 10 100 100 100 100 Decomposes violently after 10 to 15 mins. 2. Di-n-dodecyl 99 30 to 32 96 100 Stable to rapid Decomposes violently decomposition after 90 minutes 3.- Dim-tridecyl 98 43 to 45 0 O 0 3.4 Stable to rapid Stable to rapid decomposition decomposition 9 10 TABLE [1 Continued 30C and 40C Thermal Stabilitv and Safetv Tests Thermal Stability Tests of Assay Lost at Assay m.p., 30C 30C 30C 40C Safetv Tests at No. Peroxydicarbonate C 1 wk 2 wks 4 wks lwk 40C 4. Di-n-tetradecyl 98 43 0 0 Stable to rapid decomposition 5. Di-n-pentadecyl 92 51 to 53 0 0 0 Stable to rapid decomposition 6. Di-n-hcxadccyl 97 50 to 54 0 O 0 4 Stable to rapid Stable to rapid decomposition decomposition 6a. Di-n'hexadecyl El 43 to 50 L Stable to rapid Stable to rapid decomposition decomposition Crossed-out entry, such as Safety tests at 40C were done on [0 g. samples of peroxides.

These data show that there is a very sharp and unexpected improvement in thermalstability and safety of peroxydicarbonates when one goes from di-n-dodecyl peroxydicarbonate to di-n-tridecyl peroxydicarbonate (and other dialkyl peroxydicarbonates of this invention). Hence the dialkyl peroxydicarbonates of this invention are safer to store, ship and handle than the prior art dialkyl peroxydicarbonates.

EXAMPLE IX VINYL CHLORIDE SUSPENSION POLYMERlZATlON EFFICIENCIES OF DlALKYL PEROXYDICARBONATES Vinyl chloride suspension polymerizations were run at 50C for 8 hours in order to determine the amounts of initiators required at 90 percent conversion of vinyl chloride. The following recipewas employed in these polymerizations:

Ingredient Parts by Weight Vinyl chloride monomer lOO Water (triple distilled) 130 .Methocel Grade 65 HO. 50 cps'f 60 (1% aqueous soln.) Aerosol MA" 60 (1% aqueous soln.) Free-radical initiator variable Mcthyleellulosc. manufactured by Dow Chemical Co. odium sult of dihexylsulfosuccinate, manufactured by American Cyanamide Co.

PROCEDURE End-over-end tumbling at a rate of 25 revolutions per minute is employed for agitation and the polymerizations are allowed to proceed for 8 hours. At the end of that time the bottles in the safety cages are removed, cooled to 0C. and vented of vinyl chloride monomer.' Venting of unreacted vinyl chloride monomer seldom takes more than to 30 minutes, hence, post polymerizati'on is insignificant.

The amount of polymer produced is determined gravimetrically (by difference inweight) and plots of initiator required versus percent conversion are constructed for each initiator and the amount of initiator (in grams and in moles) required at 90 percent convermeans that the data for the entry was not obtained.

sion is noted. These data for the dialkyl peroxydicarbonates of this invention, art dialkyl peroxydicarbonates and dilauroyl peroxide (a diacyl peroxide used commercially'in vinyl chloride) are shown in Table III. These data show that, on a molar basis, the dialkyl peroxydicarbonates of this invention (Nos. 3, 4, 5 and 6 in Table III) are more efficient than or are as efficient as the prior art dialkyl peroxydicarbonates (Nos. 1 and 2) and are 10 times as i TABLE Ill 50C/8 Hour VinylChoride Suspension Polymerization i 9Ollgiticator l7eq6tired Perox dicarbonate at g onv. 10 g VCL .No. or Otl'ier Pei-oxide Grams Moles X"l0* l Diisopropyl 0.031 1.53 2 Di-n-dodecyl 0.057 1.23 3 Di-n-tridecyl I 0.059- L22 4 Di-n-tetradecyl 0.070 l .36 5 Di-n-pentadecyl 0.067 L24 6 Di-n-hexadecyl 0.073 1.27 7 Dilauroyl peroxide 0.550 [3.81

polymerizations than dilauroyl peroxide (industry standard).

EXAMPLE X 82C. SPl EXOTHERMS OF DIALKYL PEROXYDICARBONATES Cure characteristics of the dialkyl peroxydicarbon' ates of this invention were determined in an unsaturated polyester resin. The basic unsaturated polyester resin was a mixture of an unsaturated polyester and styrene monomer.

The unsaturated polyester was an alkyld resin made by esterifying the following components:

Component Quantity Maleic anhydride 1.0 mole Phthalic anhydride l.0 mole Propylene gl col 2.2 moles Inhibitor ad ed (hydroquinone) 0.013%

(" weight 7? based on total weight of polyester). The alkyld resin had an Acid No. OMS-50. Seven (7) parts byweight of the above polyester (alkyd resin) was diluted with three (3) parts by weight of monomeric styrene. The resulting unsaturated polyester resin had the following properties:

'a) Viscosity (Brookfield No. 2 l3.08 poise at 20 rpm.) b) Specific gravity l.l4

CURING PROCEDURE Gelation and cure characteristics of various initiators in the Unsaturated polyester resin were determined using the Standard SPI Exotherm procedure (SPI Procedure for Running Exotherm Curves Polyester Resins, published in the Preprint of the 16th Annual Conference Reinforced Plastics Division Society of the Plastics industry, lnc., February 1961).

Using this procedure at 82C. (180F.) the dialkyl TABLE IV 82C. (F.) SPl Exotherms (At Active Oxygen" Levels Equivalent to 1.0% Dibenzoyl Peroxide) Peroxydicarbonate or Other Gel, Cure, Peak No. Peroxide Min. Min. Ex0.F. Barcol l di-n-tridecyl 0.2 1.0 365 35 2 di-n-tetradecyl 0.2 1.1 355 30-35 3 di-n-pentadecyl 0.2 1.0 380 20 4 di-nhexadecyl 0.4 l .2 380 20 5 dibenzoyl 3.8 5.4 400 40-45 peroxide What is claimed is: l. Thermally safe and stable dialkyl peroxydicarbonates selected from di-n-tridecyl peroxydicarbonate, din-tetradecyl peroxydicarbonate and di-n-pentadecyl peroxydicarbonate.

2. Di-n-tridecyl peroxydicarbonate.

3. Di-n-tetradecyl peroxydicarbonate.

4. Di-n-pentadecyl peroxydicarbonate.

UXITE smnas m'rgtfr QFFHIE' f o.

CERTIFICATE OF CG RREKTITION 4 N2 3;z1y'z7s 4 Dated Iune 28, 1974 Afitori lo Joseph D Angelo V "Io-i soeftifijeid' that error appears in the above-identified patent j andthat saifiLetters Patent are hereby corrected as shown below:

*dtobout line 15, there should. be added the following foo t notes-toftlie bottom of Table II:

I -b 1TCoI n p1et loss of assay due to iolent decomposition.

' o, g ss;=1yv lost after 24 hours at 4@G-.

Signed and sealed this 22nd day 05 October 197k.

Mmm. GIBSON JR. c. MARSHALL DANN AttStiflg Officer Commissioner of Patents Fou PC4050 (10-69) USCOMM-DC 60376 as U S BOVERNHKHT HUNYING OFFICi l "i9 0" 

2. Di-n-tridecyl peroxydicarbonate.
 3. Di-n-tetradecyl peroxydicarbonate.
 4. Di-n-pentadecyl peroxydicarbonate. 